JP4218942B2 - Thin film manufacturing apparatus and thin film manufacturing method - Google Patents

Description

【００５８】
配置したパーティクル捕獲器は、以下の通りであった。
気化部内部パーティクル捕獲器 ：粒径1.0μｍ用
混合器パーティクル捕獲器 ：粒径0.5μｍ用
原料ガス・成膜ガス配管パーティクル捕獲器 ：粒径0.5μｍ用
ガスヘッドパーティクル捕獲器 ：粒径0.3μｍ用
成膜圧力は、圧力調整バルブと不活性ガスと反応ガスとにより常に５Ｔｏｒｒに調圧した。この時の装置各所の圧力は、混合器の空間Ｂにおいて１４Ｔｏｒｒ、気化部において１９Ｔｏｒｒであった。一般的に液体原料の安定気化は３０Ｔｏｒｒ以下が望ましいため、十分にその要件を満足している。
【００５９】
図１に示す半球型仕切り板を設けた混合器５内に、上記原料ガス及び反応ガスを、それぞれ、ガス導入管５−２及び５−３を経てガス導入口５−２ａ及び６−３ａから混合器内へ導入して攪拌・混合・拡散し、混合器から反応室２内に成膜ガスを導入し、この反応室内で、ＭＯＣＶＤ方法によって上記条件で基板上にＰＺＴ薄膜を形成した。また、仕切り板を設けない混合器を用いて、同じ成膜プロセスを行った。かくして形成された薄膜の膜厚分布の概略を図８（ａ）及び(ｂ)に示す。図中７１は基板、７２は膜厚の厚い部分、７３は膜厚の薄い部分を示す。 図８(ａ)から明らかなように、仕切り板無しの混合器を用いた場合、膜の薄い部分７３が原料ガス導入口側に、また、膜の厚い部分７２が反応ガス導入口側に形成された。これは、仕切り板を取り除いた空間Ａ＋Ｂ内において、空間Ａ＋Ｂの底部では上記流体解析に見られた各ガス導入口位置に対する各ガスの比較的濃い領域の反転現象が起こり、成膜ガス排出口からガスヘッドまでその反転現象を引きずったまま層流となり、基板上へその濃度分布が転写されたものと容易に推察される。この時の膜厚分布は±６．３％であった。デバイス製作上の観点からは、半導体チップの歩留まりを上げる為には膜厚分布３％以下が確実に必要であるので、仕切り板を設けない混合器を用いて得られた薄膜は、不具合である。
【００６０】
これに対し、仕切り板を設けた混合器を使用した場合（原料ガスと反応ガスとの各導入口の位置は同様である）は、図８(ｂ)から明らかなように、基板７１上に均一な膜厚を有する薄膜を膜厚分布±１．２％で連続的に製造することができた。これは、仕切り板により、各空間Ａ及びＢにおいて対流・攪拌・混合・拡散が効率よく行われ、原料ガスと反応ガスとが均一に混合されている為である。デバイス製作上の観点からは、半導体チップの歩留まりを上げるために必要な±３％以下を充分に満足していた。
図９に、パーティクル捕獲器無しの場合と、気化部、原料ガス・成膜ガス配管、混合器、ガスヘッドにパーティクル捕獲器を設置した場合と、基板毎にパーティクル捕獲器の洗浄を行った場合とについて、捕獲された積算総パーティクル数（０．２μｍ以上のサイズ）の変化を示す。図９中のパーティクル捕獲器無し以外は気化部内部には気化部材を設けてある。パーティクル数の測定は、１ロット：２５枚×４ロット＝１００枚中の各ロットの２、５、１５、２５枚目の基板について行った。
【００６１】
図９中、●で表示されているグラフは気化部内部▲１▼にパーティクル捕獲器を設置した場合、□で表示されているグラフは▲１▼＋混合器内部▲２▼とにパーティクル捕獲器を設置した場合、▲で表示されているグラフは▲１▼＋▲２▼＋原料ガス・成膜ガス配管▲３▼にパーティクル捕獲器を設置した場合、■で表示されているグラフは▲１▼＋▲２▼＋▲３▼にパーティクル捕獲器を設置し、かつ、溶媒ガス洗浄を行った場合、△で表示されているグラフは▲１▼＋▲２▼＋▲３▼＋▲４▼にパーティクル捕獲器を設置し、かつ、溶媒ガス洗浄を行った場合、○で表示されているグラフはパーティクル捕獲器を設置しなかった場合における結果を示す。
【００６２】
図９から明らかなように、装置にパーティクル捕獲器が無い場合、基板上に降り注ぐパーティクルは基板を処理するに従い増える傾向を示す。その量も既に膨大であり膜質に対する悪影響は確実であり、１００枚処理以後もさらに増加し続けるであろうと予測できる。また、初期パーティクル数が後半に比べ少ないことから、発生量は多いが気化部内部で発生量そのものが増加しているとは考えにくく、多くは装置内に付着・堆積し捕獲されたパーティクルが次第に溢れ出し下流に流れてきていると推察される。
【００６３】
気化部内部に気化部材とパーティクル捕獲器を設置した場合（図９中の▲１▼の場合）には、パーティクル総数がパーティクル捕獲器無しの場合に比べて約１／８に減少している。気化部に設置された気化部材が、下流に流れようとする原料液粒の大半を気化することで発生するパーティクルそのものが減少し、パーティクル捕獲器に流れる液粒を抑え、パーティクル捕獲器が気化部から下流に流れるパーティクルと気化部材による気化を逃れた極少量の液粒を気化したため、気化部からガスに乗り流れ出るパーティクルの多くが削減された。
【００６４】
気化部と混合器内部とにパーティクル捕獲器を設置した場合（図９中の▲１▼＋▲２▼の場合）には、混合器にパーティクル捕獲器を設置したことで、原料ガスと反応ガスとの接触の際発生するパーティクルが捕獲され、反応室内の基板で測定されるパーティクル総数が▲１▼の場合よりも減少している。しかし、１００枚処理後には総数１０００個を越え、膜質に対する悪影響は確実であり、さらに基板１００枚処理以後も増加し続けるであろうと予測できる。また、印象的なのは１ロット（基板２５枚）以後に大きな増加傾向が見られることである。このことから混合器よりも下流において成膜ガス中の既に気化した原料ガスの一部が核となり発生／成長するパーティクルの他に、ある時期からパーティクル捕獲器のパーティクルを捕獲する効力が小さくなっているため、下流に流れ、反応室で測定されるパーティクル数が増加していると考えられる。図１０(ａ)及び(ｂ)に混合器内に設置したパーィクル捕獲器の顕微鏡写真を示す。発生しているパーティクルは、０．２μｍよりも小さいサイズであるが、幾重にも重なっているパーティクル捕獲器の鋼線に付着する形で捕獲されている。この鋼線がパーティクルで覆われるとパーティクル捕獲器がパーティクルを捕獲し難くなり次第に下流にパーティクルが流れてしまう。従って、各箇所のパーティクル捕獲器の運用はパーティクルがパーティクル捕獲器の鋼線を覆い尽くさぬように、すなわち、飽和しないように、定期的に又は随時パーティクル捕獲器のパーティクルを洗浄・除去する必要がある。
【００６５】
気化部と混合器の他、原料ガス配管と成膜ガス配管にパーティクル捕獲器を設置した場合（図９中の▲１▼＋▲２▼＋▲３▼の場合）には、図９中の▲１▼＋▲２▼の場合の挙動と同様に基板毎に増加しているが、増加傾向が約１ロット遅れている。これはパーティクル捕獲器を増やしたことでパーティクル捕獲器の飽和までの時間が延ばされただけであり根本的な解決にはなっていない。
そこで、気化部、混合器、原料ガス配管、成膜ガス配管にパーティクル捕獲器を設置した状態で基板毎に溶媒ガスによる洗浄を行った場合（図９中の▲１▼＋▲２▼＋▲３▼＋▲５▼の場合）には、基板５０枚以後から若干パーティクル数は増えるが、そこからパーティクル数は約１００個以下で安定している。以上により、液体原料を気化し原料ガスとして用いるＣＶＤ法おいて装置各所に設置したパーティクル捕獲器がその機能を十分果すためには定期的に又は随時パーティクル捕獲器を洗浄することが必要である。
【００６６】
更に、この実施例ではガスヘッド内にもパーティクル捕獲器を設けている場合（図９中の▲１▼＋▲２▼＋▲３▼＋▲４▼＋▲５▼の場合）には、装置各所のパーティクル捕獲とその捕獲器の洗浄によりガスヘッド内に流れ込むパーティクル数が極小となったため、ガスヘッド内のパーティクル捕獲器は詰まり難く、他の捕獲器よりも非常にメンテナンス周期が長い。また、反応室直前の最終段階で反応室に流れ込むパーティクルも捕獲できるため、反応室内で測定されるパーティクル数は更に低減している。
装置各所に配置したパーティクル捕獲器はＰＺＴ組成比に影響を与えてしまう。図１１に気化部、混合器、原料ガス・成膜ガス配管にパーティクル捕獲器を設置した場合のＰｂ／（Ｚｒ＋Ｔｉ）、Ｚｒ／（Ｚｒ＋Ｔｉ）比の組成変化を示す。パーティクル数の測定は、１ロット：２５枚×４ロット＝１００枚中の各ロットの３、１４、２４枚目の基板について行った。
【００６７】
図１１から明らかなように、Ｚｒ／（Ｚｒ＋Ｔｉ）比に変動は無いものの、Ｐｂ／（Ｚｒ＋Ｔｉ）比が基板処理を重ねる毎に減少している。これは、装置各所に配置されたパーティクル捕獲器にＰｂ元素のみが付着していることを表し、かつ、次第にＰｂ元素の付着量が増えていることを示している。Ｐｂ元素の付着量の増加はパーティクル捕獲器に堆積するパーティクル量が上述のように経時的に変化していることと関係していると考えられる。
次に、図１２にパーティクル捕獲器無しの場合と、気化部、混合器、原料ガス・成膜ガス配管、ガスヘッドにパーティクル捕獲器を設置した場合と、基板毎にパーティクル捕獲器の洗浄を行った場合とについて、Ｐｂ／（Ｚｒ＋Ｔｉ）比の組成変化を示す。
【００６８】
図１２から明らかなように、パーティクル捕獲器を設置しない場合と、気化部内部に気化部材及びパーティクル捕獲器を設置した場合とは、基板毎のＰｂ／（Ｚｒ＋Ｔｉ）比の減少が起こらない。しかし、混合器、原料ガス・成膜ガス配管、ガスヘッドとパーティクル捕獲器を増設していくごとに、基板毎のＰｂ／（Ｚｒ＋Ｔｉ）比の減少傾向が強く現れる。Ｐｂ元素は優先的にパーティクル捕獲器に捕獲される。これに対し、基板毎のパーティクル捕獲器洗浄を行うと幾分Ｐｂ／（Ｚｒ＋Ｔｉ）比の減少傾向が抑えられる。このことから、薄膜組成制御の面でも、各箇所のパーティクル捕獲器の適用は、パーティクルがパーティクル捕獲器の鋼線を覆い尽くさぬように、すなわち、飽和しないように、定期的に又は随時パーティクル捕獲器のパーティクルを洗浄・除去する必要がある。
【００６９】
また、装置各所に配置したパーティクル捕獲器の温度を上げることでＰｂ元素の優先的付着を防ぐことが可能である。図１３に気化部、混合器、原料ガス・成膜ガス配管、ガスヘッドにパーティクル捕獲器を設置し、各温度設定を１０℃毎に挙げていった場合の基板毎のＰｂ／（Ｚｒ＋Ｔｉ）比の変化を示す。図１３から明らかなように、パーティクル捕獲器の温度を上げるごとにＰｂ／（Ｚｒ＋Ｔｉ）の減少が少なくなり、パーティクル捕獲器の温度を２０℃以上げた時点でＰｂ／（Ｚｒ＋Ｔｉ）比の減少が無くなる。
本実施例では装置各所の設定温度を２１０℃とした場合、装置各所及びパーティクル捕獲器の温度は２０５〜２１０℃であった。このことから、パーティクル捕獲器の温度を＋２０℃、つまり設定温度を２３０℃とした場合、パーティクル捕獲器の温度は２２５℃〜２３０℃となった。従って、気化部を除く装置各所のパーティクル捕獲器の温度を２２５℃以上とし、パーティクル捕獲器を定期的に又は随時に洗浄することで、パーティクル捕獲器へのＰｂ元素の優先的付着を防ぎ、組成が安定した薄膜を再現性良く連続に成膜できる。
【００７０】
ここで気化部内の気化部材とパーティクル捕獲器とについて言及する。
気化部内の気化部材とパーティクル捕獲器は気化するための最適温度に設定した。不十分な気化温度に設定すると、下流に対する影響が強すぎるために各影響が見えなくなるからである。液体原料を気化する箇所の設定温度を２４０℃とし、この時の気化部内の気化部材とパーティクル捕獲器との温度も十分な気化ができるよう２４０℃に設定した。パーティクル捕獲器の実温度は２４０〜２４５℃であった。従って、気化部内部の気化部材とパーティクル捕獲器とは、Ｐｂ元素の優先的付着が起こらない温度であった。しかし、図９の▲１▼の場合に見られるようにパーティクルが大幅に減少しているが、図１２の▲１▼の場合に見られるようにＰｂ／（Ｚｒ＋Ｔｉ）比が減少傾向を示さない。パーティクルの捕獲量に対するＰｂ／（Ｚｒ＋Ｔｉ）比の変動傾向が他のパーティクル捕獲器とは異なる。これは、温度が２４０℃以上と高いことに加え、気化部の気化部材とパーティクル捕獲器とは、下流に流れる液滴の効率的気化に重点をおいた構造とし、パーティクル捕獲器で液粒が気化するという特異な条件によるところが大きい。
【００７１】
更に、本実施例では顕著に表れなかったが、膜中のＰｂ元素が減るということは、減った元素量に相当する膜厚が減少するということである。従って、組成変動は成膜レートの不安定にもつながる。本発明者らの他の検証において、Ｐｂ／（Ｚｒ＋Ｔｉ）比が０．４減少すると膜厚が約１０〜１５ｎｍ減少し、原料ガスと反応ガスとの混合が支配的な膜厚分布には変化が無いことが確認されている（図示せず）。従って、装置各所のパーティクル捕獲器の温度を２２５℃以上とし、パーティクル捕獲器を定期的に又は随時に洗浄することでパーティクル捕獲器へのＰｂ元素の優先的付着を防ぎ、膜厚が安定した薄膜を再現性良く連続に成膜できる。
【００７２】
以上より、上記成膜例において、原料ガスと反応ガスとを均一に混合できる混合器を備え、かつ、この混合器が成膜初期と成膜終了時に膜質に影響しない配置構成とし、かつ、搬送時、成膜時、非成膜時に反応室内の圧力を一定に保ち膜剥れを抑制し、かつ、気化部内部の気化部材とパーティクル捕獲器とにより気化効率を上げて、気化部からのパーティクルの発生を抑制し、かつ、装置各所にパーティクル捕獲器を配置し、反応室に流れるパーティクルを抑え、かつ、このパーティクル捕獲器を洗浄可能な構造とし、かつ、このパーティクル捕獲器をの温度を配管温度よりも高くすることで組成変動と膜厚変動を抑えることができるため、膜厚分布・組成分布・成膜レートが良好かつ安定し、成膜ダストが少なく、連続成膜が安定して再現性良く行なえる。
【００７３】
（実施例２）
実施例１と同様にＢＳＴプロセスにおいても評価を行った。ＢＳＴの原料ガスと反応ガスである酸素ガス(Ｏ_２)とを混合する場合について、原料ガス等の種類及び設定流量を以下に示すようにして、図１に示した薄膜製造装置を用いてＢＳＴ薄膜を製造した。

【００７４】
配置したパーティクル捕獲器は、以下の通りであった。
気化部内部パーティクル捕獲器 ：粒径1.0μｍ用
混合器パーティクル捕獲器 ：粒径0.5μｍ用
原料ガス・成膜ガス配管パーティクル捕獲器 ：粒径0.5μｍ用
ガスヘッドパーティクル捕獲器 ：粒径0.3μｍ用
成膜圧力は、圧力調整バルブと不活性ガスと反応ガスとにより常に８Ｔｏｒｒに調圧した。
図１に示す半球型仕切り板を設けた混合器５内に、上記原料ガス及び反応ガスを、それぞれ、ガス導入管５−２及び５−３を経てガス導入口５−２ａ及び６−３ａから混合器内へ導入して攪拌・混合・拡散し、混合器から反応室２内に成膜ガスを導入し、この反応室内で、ＭＯＣＶＤ方法によって上記条件で基板上にＢＳＴ薄膜を形成した。また、仕切り板を設けない混合器を用いて、同じ成膜プロセスを行った。その結果、本発明の場合、実施例１と同様の効果が得られた。
【００７５】
（実施例３）
実施例１と同様にＣｕプロセスにおいても評価を行った。Ｃｕ薄膜の原料ガスと反応ガスである水素ガス（Ｈ_２）等の種類及び設定流量を以下に示すようにして、図１に示した薄膜製造装置を用いてＣｕ薄膜を製造した。

【００７６】
配置したパーティクル捕獲器は、以下の通りであった。
気化部内部パーティクル捕獲器 ：粒径5.0μｍ用
混合器パーティクル捕獲器 ：粒径0.3μｍ用
原料ガス・成膜ガス配管パーティクル捕獲器 ：粒径0.3μｍ用
ガスヘッドパーティクル捕獲器 ：粒径0.1μｍ用
成膜圧力は、圧力調整バルブと不活性ガスと反応ガスとにより常に０．８Ｔｏｒｒに調圧した。
図１に示す半球型仕切り板を設けた混合器５内に、上記原料ガス及び反応ガスを、それぞれ、ガス導入管５−２及び５−３を経てガス導入口５−２ａ及び６−３ａから混合器内へ導入して攪拌・混合・拡散し、混合器から反応室２内に成膜ガスを導入し、この反応室内で、ＣＶＤ方法によって上記条件で基板上にＣｕ薄膜を形成した。また、仕切り板を設けない混合器を用いて、同じ成膜プロセスを行った。その結果、本発明の場合、実施例１と同様の効果が得られた。
【００７７】
本発明の薄膜製造装置及び製造方法は、上記実施例の他に、液体原料を気化し原料ガスとして用いる全てのＣＶＤ成膜の場合に適用可能である。
本発明によれば、上記実施例の他に、液体原料を気化して原料ガスとして用い、質量差の有る原料ガスと反応ガスとを均一に混ぜることが可能であり、また、反応室圧力を原料元素に合わせた圧力とし、常に一定に維持可能であり、また、気化条件（気化温度、キャリアガス、気化圧力）を適切に設定すれば、原料液の種類に依らず原料液粒を効率良く気化することも可能であり、また、気化部を含む装置各所にパーティクル捕獲器の目の粗さを適切に選択したものを適宜配置することにより、反応室に流れ込むパーティクルを抑えることも可能であり、また、装置各所のパーティクル捕獲器の温度を原料に合わせた配管温度よりも高く適切な温度とすることで、反応に必要な特定の元素がパーティクル捕獲器に付着することを防ぐことも可能であり、さらに、この装置各所に配置したパーティクル捕獲器や装置各所の内部や配管が洗浄可能である。このため、液体原料を気化したガスと反応ガスとを成膜ガスとして用いるＣＶＤ法において、膜厚分布・組成分布・成膜レートが良好かつ安定し、成膜ダストが少なく、連続成膜が安定して再現性良く行なえる薄膜製造装置及びその製造方法を確立することが可能である。
【００７８】
【発明の効果】
以上のように、本発明によれば、ＣＶＤ薄膜製造装置において、気化部、混合室、ガスヘッド及びガス配管に配置したパーティクル捕獲器により捕獲されたパーティクルや、ガス配管を含めて装置の各構成要素で発生しかつこれらに付着したパーティクルを洗浄・除去する構造としたことにより、装置各所のパーティクル捕獲器の寿命を延ばし、その結果、装置稼働時間を延ばすことができる。また、この洗浄によりパーティクル捕獲器に付着する反応に必要な特定元素の量を低減でき、その結果、膜組成変動や膜厚変動を抑えることができ、膜厚分布・組成分布・成膜レートが良好で安定し、成膜ダストが少なく、連続成膜が安定して再現性良く行える。
【００７９】
本発明によれば、この洗浄による効果に加えて、原料ガスと反応ガスとを均一に混合できる混合器を備えているので、混合のための乱流を反応室に持ち込まず、膜厚分布とその再現性が向上し、また、この混合器が成膜初期と成膜終了時に膜質に影響しない装置構造・配置としたので、膜質とその再現性が向上する。さらに、このような構造において、搬送時、成膜時、非成膜時に反応室内の圧力を一定に保つことができるようにしたので、膜剥れを抑制し、装置の稼働時間を延ばし、パーティクルの発生を低減することができる。さらにまた、気化部内部の気化部材とパーティクル捕獲器とにより、気化効率を上げて気化部からのパーティクルの発生を抑制し、その下流に位置する装置各所のパーティクル捕獲器の寿命を延ばして、装置稼働時間を延ばすことができると共に、装置各所に配置したパーティクル捕獲器により、反応室に流れるパーティクルを抑え、製品に不具合を来す基板上のパーティクルを低減することができるという効果がある。
【図面の簡単な説明】
【図１】 本発明の薄膜製造装置の構成を示す概略構成図。
【図２】 図１に示す本発明の薄膜製造装置における気化システムの概略構成図。
【図３】 図１に示す本発明の薄膜製造装置における気化部内部の概略構成図であり、(ａ)はその断面図、(ｂ)はその斜視図。
【図４】 図１に示す本発明の薄膜製造装置における混合器の概略断面図。
【図５】 図４に示す混合器のガス分布とガス流れを説明するための図であり、(ａ)は混合器内の空間Ａ部分の断面図、(ｂ)は混合器の上面図。
【図６】 連続成膜における基板毎の総パーティクル数の推移を示すグラフ。
【図７】 本発明における反応室内の排気ガスの流れを説明するための反応室の一部の断面図であり、(ａ)は基板ステージが基板搬送位置にある場合の断面図、(ｂ)は基板ステージが成膜位置にある場合の断面図。
【図８】 仕切り板が無い場合と有りの場合の成膜結果を示す基板上面図。
【図９】 各連続成膜における基板毎の総パーティクル数の推移を示すグラフ。
【図１０】 混合器内部に設けられたパーティクル捕獲器の電顕写真であり、(ａ)はその表面状態を示す電顕写真、(ｂ)はその拡大写真。
【図１１】 気化部＋混合器＋原料ガス・ガス配管にパーティクル捕獲器設置した場合の総合影響による組成変化（Ｐｂ／（Ｚｒ＋Ｔｉ）とＺｒ／（Ｚｒ＋Ｔｉ））を示すグラフ。
【図１２】 各パーティクル捕獲器設置条件での組成変化（Ｐｂ／（Ｚｒ＋Ｔｉ））を示すグラフ。
【図１３】 気化部＋ガス配管＋混合器＋ガスヘッドにパーティクル捕獲器を設置し、さらに基板毎の、パーティクル捕獲器を溶媒ガス洗浄した時におけるパーティクル捕獲器温度の組成（Ｐｂ／（Ｚｒ＋Ｔｉ））への影響を示すグラフ。
【符号の説明】
１ 排気システム １ａ 圧力調整バルブ
２ 反応室 ２−１ 基板ステージ
２−２ スリーブ部材 ２−３ ガスリング
３ ガスヘッド ４ 成膜ガス配管
５ 混合器 ５−１ 仕切り板
５−２ 原料ガス導入管 ５−２ａ 原料ガス導入口
５−３ 反応ガス導入管 ５−３ａ 反応ガス導入口
５−４ ガス吹き出し口 ５−５ 成膜ガス導入口
６ 原料ガス配管 ７ 気化システム
７ａ 原料液供給部 ７ｂ 気化部
７ｂ−１ ノズル ７ｂ−２、７ｂ−３ 気化部材
７ｂ−４ パーティクル捕獲器 ８ 配管
９、１３ 熱交換器 １０、１１、１２ 配管
２０、２１、２２、２３ マスフローコントローラ
２０−１、２１−１、２２−１、２３−１ 反応ガス／不活性ガス源
Ａ、Ｂ、Ｃ 原料液 Ｄ 溶媒供給部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thin film manufacturing apparatus and a thin film manufacturing method, and more particularly to a thin film manufacturing apparatus provided with particle cleaning means used when manufacturing a thin film by a CVD process such as MOCVD, and a method of manufacturing a thin film using this apparatus. .
[0002]
[Prior art]
Conventionally, a gas obtained by vaporizing a raw material liquid (a liquid raw material or a liquid in which a solid raw material is dissolved) is used as a raw material gas, and a gas obtained by mixing this raw material gas and a reaction gas having a lighter mass than the raw material gas is used as a film forming gas. In the CVD process to be used, in order to obtain a good CVD film, uniform mixing of the source gas and the reaction gas in the film forming gas is indispensable. In the method of mixing the source gas and the reaction gas in the reaction chamber, uniform mixing of the source gas and the reaction gas is difficult, and the concentration distribution of the source gas affects the film thickness distribution. Since turbulent flow is generated in the room, the flow cannot be controlled, and as a result, reproducible and stable film formation cannot be performed. Therefore, in the CVD process in which the raw material liquid is vaporized and used as the raw material gas, a mixer that can uniformly mix the raw material gas and the reactive gas having a mass difference and does not bring uncontrollable turbulent flow into the reaction chamber is required. ing. Therefore, the present inventors have proposed a mixer that can uniformly mix gases having a mass difference and does not bring uncontrollable turbulent flow into the reaction chamber (Japanese Patent Application No. 2001-369279).
[0003]
Further, in order to satisfy the recent demand for high integration of semiconductor elements, when forming a thin film by a CVD method such as MOCVD method, the fine particles containing foreign particles and moisture contained in the source gas can be as much as possible. It is necessary to reduce it. Conventionally, for example, in order to remove these particles to the ppt level, it has been proposed to introduce a raw material gas into a reaction chamber which is a vacuum chamber after passing through a filter member having high filtration characteristics. The present inventors provide particles trapped in the vaporization chamber and the piping by providing a temperature-controllable particle trap between the source gas generation vaporization chamber and the mixing chamber and on the downstream side of the mixing chamber, respectively. Has been proposed (Japanese Patent Application No. 2002-117123).
[0004]
[Problems to be solved by the invention]
In the conventional apparatus including the thin film manufacturing apparatus in Japanese Patent Application No. 2001-369279, the reaction chamber and the mixing chamber are directly connected without a pipe, that is, above the reaction chamber so as to constitute a part of the reaction chamber. A mixing chamber is provided, and a valve for introducing / not introducing the raw material gas into the reaction chamber is on the primary side of the mixer. Therefore, when this apparatus is used, the flow rates of the source gas and the reaction gas introduced into the mixing chamber are unstable for a moment at the initial stage of film formation (immediately after the source gas is introduced into the mixer). A film forming gas with insufficient mixing with the reaction gas and an insufficient mixing ratio is introduced into the reaction chamber. As a result, the thin film growth control at the initial stage of film formation, which is the most important in CVD film formation, is incomplete.
[0005]
Further, when the source gas introduction / non-introduction valve into the reaction chamber is on the primary side of the mixing chamber, it is introduced into the mixing chamber when the source gas valve is switched to the non-introduction side at the film formation end stage. The flow rate of the source gas and the reactive gas becomes unstable for a moment, and there is a film forming gas remaining in the mixing chamber, that is, a film forming gas with an insufficient mixing ratio between the source gas and the reactive gas. When it is introduced into the reaction chamber, unintended film formation is performed on the substrate or the like. Recently, a small-sized mixer has been developed, but even in this case, it is unavoidable that excessive film formation corresponding to the internal volume occurs.
As described above, the arrangement of the mixer in the thin film manufacturing apparatus affects the film formation.
[0006]
In general, when a thin film is manufactured by the MOCVD method, a mixed gas (deposition gas) composed of vaporized source gas and reaction gas is introduced into a reaction chamber that is a vacuum chamber, and is placed on a substrate stage disposed in the reaction chamber. A film is formed on the placed substrate by a gas phase chemical reaction. A gas head such as a shower plate is disposed on the upper surface of the reaction chamber so as to face the substrate stage, and a gas mixing chamber is directly connected to the gas head without a pipe. At the time of film formation, the raw material gas and the reaction gas supplied to the mixing chamber are introduced as a mixed gas having a predetermined mixing ratio into the reaction chamber evacuated to a predetermined degree of vacuum through a gas head to form a thin film. The In this case, in order to form a thin film having a uniform film quality and film thickness distribution on the substrate, a uniform flow distribution, uniform concentration distribution, and uniform temperature distribution of the deposition gas in the reaction chamber or directly above the substrate are required. In addition, the smaller the fine particles contained in the deposition gas, particularly the raw material gas, the better.
[0007]
However, when forming a thin film by the MOCVD method, even if the source gas is introduced into the reaction chamber after passing through the filter member as in the above prior art, the particles are not completely removed only through the filter member. There is a problem and a problem that the life of the filter member is short. In order to prevent such particles from adhering to various parts of the apparatus and to suppress the pressure increase in the filter caused by the accumulation of particles trapped in the filter, these particles can be easily cleaned and removed periodically, and continuous formation is performed. There is a demand for a thin film manufacturing apparatus and a manufacturing method with a long maintenance cycle in which a film can be formed for a long time.
[0008]
In addition, as in Japanese Patent Application No. 2002-117123, in a film forming apparatus provided with a particle trap to prevent inflow of particles into the film forming chamber, a source gas, a reactive gas, When starting to flow a gas such as a carrier gas, a large pressure difference may temporarily occur between the primary side and the secondary side of the particle trap disposed in the mixing chamber 3 shown in FIG. As a result, particles are rolled up from the particle trap in the mixing chamber 3 and flowed out to the downstream side, and an increase in the number of particles on the initial wafer of the production lot was observed. In this film forming apparatus, at the time of starting film forming for each wafer, switching from the vent line of the source gas to the film forming chamber is performed by opening and closing the valve, and particles are generated at that time. This is considered to be due to temporary pressure fluctuations between the primary and secondary sides of the particle trap, and the technical goal of reducing the total number of particles with a size of 0.2 μm or more is to be achieved. Has become an obstacle. In this case as well, the particles can be easily cleaned and removed periodically, in order to adhere to various parts of the device, and to suppress the pressure increase in the trap due to the accumulation of particles trapped in the particle trap. There is a demand for a thin film manufacturing apparatus and manufacturing method that can form a film for a long time and have a long maintenance cycle.
[0009]
Furthermore, in order to clean the particle traps such as filters and particle traps provided at various locations in the conventional apparatus, it is necessary to remove them once and clean or replace them. Further, even if the solvent gas can be cleaned without removing it, the solvent gas containing a large amount of particles is introduced into the reaction chamber. In particular, the particle trap provided in the mixer, which captures the particles generated at the moment when the source gas and the reaction gas contact each other after the two gases are uniformly mixed, is periodically cleaned. Although it is necessary, the conventional apparatus is not configured to be easily cleaned with a solvent gas or the like, and has to be removed once and cleaned or replaced. In the conventional apparatus, it is difficult to easily clean and remove particles adhering to the inside of each component including piping.
[0010]
An object of the present invention is to solve the above-described problems of the prior art, and has a structure in which particles generated in various parts of the apparatus can be easily cleaned and removed without bringing them into the reaction chamber, and the film thickness distribution, composition distribution, An object of the present invention is to provide a thin film manufacturing apparatus and a thin film manufacturing method capable of stably performing a continuous film formation by a CVD method with a high reproducibility and effectively over a long period of time.
[0011]
[Means for Solving the Problems]
  In order to solve the above-described problems, a membrane manufacturing apparatus of the present invention includes a raw material supply unit that supplies a raw material liquid obtained by dissolving a liquid or solid raw material in a solvent, a vaporization system having a vaporization unit, a mixer, a reaction chamber, and an exhaust. In the membrane manufacturing apparatus including the system, the vaporization system, the mixer, the reaction chamber, and the exhaust system are respectively connected by piping, and the temperature-controlled vaporization member is disposed inside the vaporization unit. Provided, the mixer is provided with raw gas and reaction gas introduction pipes such that the respective gas introduction ports face each other, and has a quadratic curve shape that is convex toward the downstream side in the inside thereof. A partition plate is provided to divide the mixer into two spaces.Equivalent to 1/2 of the vertical distance from the upstream ceiling to the downstream bottomA gas outlet is provided at a position so that the source gas and the reaction gas are uniformly mixed in the mixer, and the resulting film forming gas is introduced from the mixer to the gas head of the reaction chamber via a pipe. Configured so that a pressure regulating valve is provided between the reaction chamber and the exhaust system, a particle trap is disposed at a predetermined position of the apparatus, and a solvent gas vaporized in the vaporizing section. So that the particles generated in the various parts of the apparatus from the vaporization section to the reaction chamber and adhered to the various parts of the apparatus can be washed and removed.The raw material liquid supply part is provided with a solvent supply part for supplying the same solvent for particle cleaning / removal as the solvent for dissolving the raw material.It is characterized by that.
[0013]
As described above, the solvent supplied from the solvent supply unit is vaporized in the vaporization unit, and the vaporized solvent gas is caused to flow through the pipe to regularly generate particles that are generated and adhered to various parts of the apparatus from the vaporization unit to the reaction chamber. In order to maintain the performance of the particle trap at a constant level, the specific elements in the source gas do not adhere at an accelerated rate, so that a constant amount of film forming gas can be obtained. Can be introduced into the reaction chamber. In addition, the particle trap does not affect the process in the long term, and there is no pressure increase in each particle trap placed in the equipment due to particle clogging, so the particle trap affects the process in the long term. There is no giving. Thus, the maintenance cycle due to particle clogging can be extended, the number of particles can be reduced in the long term, the film thickness distribution / composition distribution / film formation rate is stable, and continuous film formation can be performed stably with good reproducibility. Membrane production equipment with excellent productivity and productivity.
[0014]
  In the present invention, a particle trap for capturing particles generated when the raw material liquid is vaporized is provided inside the vaporization section, and is generated in a gas path from the vaporization section to the reaction chamber through the mixer. In order to capture particles, a particle trap may be arranged at a predetermined location of the apparatus. By configuring in this manner, particles based on the residue generated when the raw material liquid is vaporized are hardly taken out of the vaporization system, so that the generated particles are not brought into the mixer and the reaction chamber. Easy to clean and remove regularly. As a result, it is possible to provide a film manufacturing apparatus with excellent mass productivity and productivity that can stably perform continuous film formation with high reproducibility, with stable film thickness distribution, film composition distribution, and film formation rate.
[0015]
  In the present invention, the particle trap may be disposed in a pipe between the vaporizer and the mixer, and the particle trap may be disposed in the mixer. Further, the particle trap may be arranged in a gas head installed at the upper part of the reaction chamber. In this case, the particles captured by the particle traps may be cleaned and removed by flowing a solvent gas that is vaporized in the vaporization section. Thereby, the film-forming gas with few particles can be stably supplied to the reaction chamber, and the captured particles can be easily cleaned and removed periodically. As a result, it is possible to provide a film manufacturing apparatus excellent in mass productivity and productivity as described above.
[0019]
As described above, in the mixer used in the membrane manufacturing apparatus of the present invention, the inlets for the source gas and the reaction gas are arranged to face each other and mixed by a partition plate having a quadratic curve shape such as a hemispherical shape. The position and size of the holes provided in the partition plate are divided so that there is a difference in the volume inside the chamber, and the mixed gas of the raw material gas and the reaction gas is smoothly discharged from the narrow space to the wide space. Is appropriately designed to provide a pressure difference between the two spaces. Therefore, the process of stirring and mixing the raw material gas and the reactive gas by intense convection generated by the partition plate, and the process of diffusing the mixed gas of the raw material gas and the reactive gas that have come out from the hole of the partition plate in a wide space The two processes can be mixed uniformly. And the internal pressure of the vaporization part of the primary side is made low by keeping mixer internal pressure low.
[0020]
In other words, the two processes of stirring and mixing the source gas and the reaction gas and then uniformly mixing by diffusion are performed in one mixer, so that the source gas and the reaction gas can be mixed without using a complicated structure. These gases can be mixed uniformly without the volume of the mixer being affected by the flow rate and type. By mixing the source gas and the reaction gas uniformly and then introducing them into the reaction chamber, the turbulence generated during the mixing affects the film formation compared to mixing the source gas and the reaction gas in the reaction chamber. There is nothing. Also, by keeping the pressure inside the vaporization section low, the maintenance cycle of the vaporization section is lengthened, and it is possible to supply a stable source gas, and thus supply a film-forming gas to the reaction chamber, so that it is generated on the substrate. The film quality / distribution of the film can be improved, and the film quality / distribution can be stabilized.
[0021]
Further, as described above, a valve for introducing / not introducing the film forming gas into the reaction chamber is arranged on the secondary side of the mixer so that the film forming gas can be switched instantaneously. It is possible to prevent unintentional film formation on the substrate by the film gas, and as a result, it is possible to improve the film quality / film performance and to stabilize the film quality / film composition distribution / film thickness distribution.
The gas outlet provided in the partition plate of the mixer used in the present invention provides a pressure difference between one space and the other space by appropriately setting the position and size thereof, and thereby in one space. The gas having different weights is uniformly mixed by the strong convection generated in the gas, and the mixed gas is diffused from one narrow space into the other wide space.
[0022]
  About this gas outletOnIn the apparatus having the solvent gas cleaning means, it is preferable that the gas outlet is further provided at a position corresponding to about ½ of the vertical distance from the upstream ceiling portion to the downstream bottom portion of the partition plate. Thereby, the uniformly mixed gas is efficiently diffused from one space to the other space, and the process of stirring, mixing, and diffusing can be performed conveniently.
  Further, in the apparatus having the above solvent gas cleaning means, the reaction chamber is further protected so that the pressure in the reaction chamber does not fluctuate when introducing / not introducing the film forming gas into the reaction chamber (including when the apparatus is on standby and transported). At the same time as the normal pressure control by the pressure control valve provided between the exhaust system and the exhaust system, it is structured so that the same amount of gas can be flowed even during non-film formation (including when the system is on standby and transported), and An inert gas source and a reaction gas source are connected to the secondary side of the mixer together with a flow rate control system, and an inert gas or a reaction gas or a mixed gas of an inert gas and a reaction gas in an arbitrary ratio is introduced into the reaction chamber. It is characterized by having a structure capable of controlling the pressure in the reaction chamber.
[0023]
  Device standbyWhenContinuous film formationThe film production is repeatedIn the production operation cycle of equipmentA structure capable of continuously performing pressure control by the pressure regulating valve and pressure control by introducing the inert gas or reaction gas or an inert gas and a reaction gas in an arbitrary ratio into the reaction chamber.It is characterized by that. Thereby, continuous film formation with little film formation dust is performed stably and with good reproducibility.
  In the present invention, in the apparatus having the solvent gas cleaning means, an inert gas source and a reactive gas source are also connected to a reaction chamber (or a gas head) together with a flow rate control system, so that the inert gas or reaction A gas or a mixed gas of an inert gas and a reaction gas in an arbitrary ratio is introduced into the reaction chamber, and the temperature of the substrate can be increased by these gases.
  Further, in the present invention, the reaction chamber, the inert gas source and the reactive gas source are connected via a flow rate control system, and the inert gas or the reactive gas or the inert gas and the reactive gas in any ratio are connected. The substrate can be heated by the heating means while directly introducing the mixed gas into the reaction chamber.
[0024]
  In the present invention,A valve for introducing / not introducing the film forming gas into the reaction chamber is arranged on the secondary side of the mixer. By installing the gas valve in this manner, it is possible to shut off the vaporizer, the mixer, and the exhaust system, and maintenance of these elements is facilitated.
  Furthermore, in the present invention,A step of stirring and mixing the source gas and the reaction gas, a step of diffusing a film forming gas composed of the source gas and the reaction gas obtained by stirring and mixing, and a diffusion film forming gas containing almost no particles. Introducing into the reaction chamber, forming a film on the object to be deposited in vacuum, and particles adhering or captured in various parts of the apparatus from the vaporization section to the gas head provided at the top of the reaction chamber And a step of cleaning and removing with a gas of the same solvent as the solvent of the raw material liquid, and preferably using the above-described film manufacturing apparatus.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a thin film manufacturing apparatus according to the present invention will be described below with reference to the drawings.
FIG. 1 is an arrangement diagram showing a schematic configuration of a thin film manufacturing apparatus according to the present invention, and FIG. 2 is a vaporization system constituted by a raw material liquid supply unit and a vaporization unit, which is provided in addition to the raw material liquid supply unit. FIG. 3A is a schematic diagram for explaining the structure in the vaporization unit. FIG. 3A and FIG. 3B are schematic diagrams for explaining the structure in the vaporization unit. 4 is a schematic cross-sectional view for explaining the internal structure of the mixer, and FIG. 5 (a) is a schematic cross-sectional view for explaining the internal structure of the space A in the mixer and the gas flow path. FIG. 5B is a schematic top view for explaining the internal structure of the mixer and the gas flow path. 1 to 5, the same constituent elements are given the same reference numerals.
[0026]
As shown in FIG. 1, the thin film manufacturing apparatus according to the present embodiment includes a reaction chamber 2 connected to an evacuation system 1 via a pressure adjusting valve 1a, and a gas head 3 provided on the upper portion of the reaction chamber. It has a mixer 5 connected to be separated by a membrane gas pipe 4 and a vaporization system 7 connected to the mixer 5 by a raw material gas pipe 6. In order to keep the vaporized source gas at a temperature at which the vaporized source gas is not liquefied / deposited / deposited on the apparatus components including the gas pipe, various valves, mixer, and gas head from the vaporization system 7 to the reaction chamber 2, heating means such as a heater And a heat exchanger. The pipe 6 between the vaporization system 7 and the mixer 5 is provided with a valve V3, and the pipe 8 between the vaporization system 7 and the exhaust system 1 is provided with a valve V4, whereby the vaporization system 7 and the mixer are provided. 5. The exhaust system 1 can be shut off. This is because the maintenance cycles of the components of the vaporization system 7, the mixer 5 and the exhaust system 1 are different, so that substances such as moisture that adversely affect film formation due to release to the atmosphere are avoided from adhering to these components. Is the purpose. When maintenance is performed with one component open to the atmosphere, the vacuum can be maintained without releasing the other two components to the atmosphere.
[0027]
Here, when the particle trap cleaning for each substrate is insufficient, particles remain in the particle trap. When the gas flow changes in this state, the particles captured by the particle trap may flow downstream.
In the graph shown in FIG. 6, a significant increase in particles at the initial stage of the lot is observed for every 1 to 100 substrate processing lots (25). This occurs because, in the control program of the apparatus, the gas for pressure control stops for a moment every time lot processing starts and then flows after the gas stops, so that particles in various parts of the apparatus flow into the downstream (reaction chamber). Conventionally, a general apparatus normally closes (or closes for a moment) a gas valve as an operation check at the start of lot processing (it is supposed to do so for a state check / operation check). However, in an apparatus using a particle trap, it is a problem that instantaneous changes in gas flow (pressure change, flow rate change, change in flow rate, etc.) cause particles captured by the particle trap to flow downstream. is there.
[0028]
In order to suppress this increase in particles, gas introduction and pressure control will not stop for a moment in the production operation cycle of the apparatus standby → continuous film formation → apparatus standby → continuous film formation unless otherwise specified / set. Improved device control system to do so. This control system is used between the 100th and 101st sheets (4th and 5th lots). As a result, the number of particles measured on the substrate is remarkably reduced if this control system does not cause an instantaneous gas stop after the 100th sheet (between lots). Of course, the gas flow rate control / pressure control does not stop even for a moment between the substrates in the lot.
[0029]
Hereafter, each said element is demonstrated in detail.
In the reaction chamber 2, a substrate stage 2-1 having a substrate heating unit for placing a substrate as a film formation target is disposed, and a film is formed on the heated substrate from the gas head 3. Gas is introduced. Excess film forming gas that has not been used for the reaction with the substrate and the by-product gas with the film forming gas generated by the reaction with the substrate and the reactant gas are exhausted by the exhaust system 1. The gas head 3 provided in the upper part of the reaction chamber 2 may be provided with a particle trap P6 as a filter for capturing particles present in the film forming gas. The gas head 3 is appropriately heated and maintained at a temperature at which the introduced gas is not liquefied / deposited / formed. Further, it is desirable that the particle trap is provided immediately before the shower hole of the gas head and is appropriately adjusted to a temperature at which a specific vaporized raw material element necessary for the reaction is not attached and trapped.
Various film forming pressure conditions can be easily accommodated by the pressure regulating valve 1a provided between the exhaust system 1 and the reaction chamber 2.
[0030]
The mixer 5 is connected to the vaporization system 7 by a pipe 6 provided with a valve V3, and is connected to a gas source 20-1 (for example, via the valve V5 and the heat exchanger 9, and then the mass flow controllers 20 and 21, respectively) Reaction gas source) and 21-1 (for example, an inert gas source). The film-forming gas uniformly mixed in the mixer 5 is introduced into the gas head 3 through the pipe 4 provided with the valve V1, and is formed on the substrate stage 2-1 without becoming a laminar flow in the reaction chamber 2. It is supplied to the surface of the film-forming target placed. In addition to the reactive gas source, the reactive gas source includes an inert gas such as a carrier gas (for example, N₂Etc.) are also connected, and each supply system conveys the reaction gas and carrier gas from the gas source to the mixer 5 through the flow rate regulator and the heat exchanger by adjusting the valve element. It is configured as follows. The reaction gas may be a gas that matches the source gas, for example, H₂Etc. NH during nitriding₃Etc., O during oxidation₂Etc. The source gas is a gas obtained by vaporizing a source solution obtained by dissolving an organometallic compound or the like in an organic solvent.
[0031]
In the mixer 5, the appropriately heated reaction gas supplied from the reaction gas source and the raw material gas generated by the vaporization system 7 and sent through the pipe 6 maintained at a temperature at which liquefaction / deposition / film formation is not introduced are introduced. -A film forming gas (reaction gas + source gas) is obtained by mixing. This source gas is a gas in which one kind or a plurality of kinds of gases are mixed. The film forming gas thus obtained is introduced into the reaction chamber 2 through the pipe 4.
The pipes 4 and 6 are connected by a VCR joint, and the VCR gasket of each joint of some pipes is preferably a VCR type particle trap in which a hole is not a ring but a particle trap. . The joint with this VCR type particle trap is set and maintained at a temperature higher than the temperature at which the source gas is not liquefied / deposited, and does not attach or trap the specific vaporized source elements necessary for the reaction. desirable.
[0032]
In the film forming gas line between the mixer 5 and the reaction chamber 2, valves (V 1 and V 2) for switching the film forming gas are provided on the secondary side of the mixer 5. The downstream sides of the valves V1 and V2 are connected to the reaction chamber 2 and the exhaust system 1, respectively. During film formation, valve V1 is opened and valve V2 is closed, and after film formation is completed, valve V2 is opened and valve V1 is closed. During the initial few moments when the raw material gas or the reaction gas is introduced into the mixer 5, the mixing is not uniform and unstable. Therefore, the valve V 1 is closed and the valve V 2 is opened. The mixed gas is allowed to flow, and after the mixing is stabilized, the valve V2 is closed and the valve V1 is opened so that the film forming gas can be introduced into the reaction chamber 2 through the gas head 3. At the end of the film formation, the valve V2 is opened for a moment, the valve V1 is closed, and surplus film formation gas in the mixer 5 is allowed to flow into the exhaust system 1, thereby instantaneously introducing the film formation gas into the reaction chamber. It is constituted so that it is not introduced into the reaction chamber 2.
[0033]
The vaporization system 7 is comprised from the raw material supply part 7a and the vaporization part 7b, as shown in FIG.2, FIG.3 (a) and FIG.3 (b). This vaporization system pressurizes and conveys raw material liquids A, B, and C obtained by dissolving a liquid / solid raw material in an organic solvent with a pressurized gas (for example, an inert gas such as He gas), The respective flow rates are controlled by the respective liquid flow rate controllers A-1, B-1, and C-1, and are conveyed to the vaporizing unit 7b. Further, the raw material supply unit 7a is provided with a solvent supply unit D made of a solvent which is the same solvent as the solvent in the raw material liquid, and the flow rate of the solvent is controlled by the flow rate controller D-1 to the vaporization unit. The solvent gas for particle cleaning / removal can be obtained by introducing and vaporizing by the vaporizing unit 7b.
[0034]
The vaporization unit 7b efficiently vaporizes the raw material liquid whose flow rate is controlled, and supplies the raw material gas obtained by vaporization to the mixer 5 and also supplies the solvent supplied from the solvent supply unit D. Is efficiently vaporized, and the solvent gas can be supplied downstream from the vaporization section. In the vaporization unit 7b, when there is one liquid source, a single liquid can be mixed and when there are a plurality of liquid sources, a plurality of source liquids can be mixed and vaporized. When vaporizing the raw material liquid, not only vaporize the liquid droplets of the raw material liquid, but also apply gas to the liquid droplets, apply physical vibrations, or apply ultrasonic waves to the vaporization part wall surface. In addition, it is preferable to introduce vaporization as finer liquid particles through the nozzle 7b-1 into the vaporization section to evaporate the vaporization efficiency. In order to reduce the droplet vaporization load by the particle trap, which will be described later, in order to reduce the droplet or liquid droplet as much as possible in the portion to be vaporized efficiently, and within the vaporization unit 7b, Al It is preferable to arrange the vaporizing members 7b-2 and 7b-3 made of a material having good thermal conductivity such as. In addition, inside the vaporizing section 7b, particles based on residues generated when the raw material liquid is vaporized are not discharged outside the vaporizing section, and a small amount of liquid droplets are sucked out of the vaporizing section by vacuum. In order to enable complete vaporization, a particle trap 7b-4 may be provided. In this vaporization member and particle trap, appropriate droplets and fine liquid particles that are in contact with these vaporizers can be properly vaporized, and appropriate vaporizer elements that are necessary for the reaction are not attached or captured. It is preferable that vaporization conditions are maintained at the temperature.
[0035]
Next, the mixer will be described in more detail with reference to FIG. 4, FIG. 5 (a) and FIG. 5 (b). In FIGS. 5 (a) and 5 (b), solid and dotted lines, and alternate long and short dashed lines indicate the tendency of the fluid analysis results obtained by computer simulation of the reaction gas flow and the raw gas flow, respectively. Examples of gas flow and gas distribution are described below.
As shown in FIG. 4, the outside and inside of the mixer 5 are cylindrical, and the inside of the mixer is partitioned into two spaces A and B having different volumes by a hemispherical partition plate 5-1. In the space A, a raw material gas introduction pipe 5-2 for introducing at least one kind of raw material gas and a reaction gas introduction pipe 5-3 for introducing a reaction gas are attached, and each of these gas introduction pipes is installed. The source gas introduction port 5-2a and the reaction gas introduction port 5-3a are arranged to face each other so that each gas flow is introduced into the space A.
[0036]
The source gas and the reaction gas introduced to face each other through the gas introduction ports 5-2a and 5-3a are convected, stirred, and mixed in the space A by the hemispherical partition plate 5-1. The source gas and the reaction gas stirred and mixed in the space A exit to the space B from one mixed gas outlet 5-4 provided in the partition plate on the source gas inlet 5-2a side. When the mixed source gas and the reaction gas exit from the space A to the space B through the gas outlet 5-4, a gas diffusion phenomenon occurs due to a difference in pressure and volume in the space, and is mixed uniformly. The uniformly mixed source gas and reaction gas are supplied into the reaction chamber 2 via the gas head through the pipe 4 that leads from the film formation gas inlet 5-5 to the gas head 3 (FIG. 1) as a film formation gas. It is introduced and reaches the substrate to be processed. In this case, since the source gas and the reaction gas are uniformly mixed in advance and introduced into the reaction chamber, the turbulent flow generated when the source gas and the reaction gas are mixed in the mixer is not brought into the film formation chamber, It does not affect the film formation. Inside the mixer 5, a particle trap may be provided to capture a small amount of particles generated during mixing, and to take care not to attach or trap specific vaporized source elements necessary for the reaction. .
[0037]
As shown in FIG. 4, the mixed gas outlet 5-4 from the space A to the space B is a vertical direction of a straight line connecting the source gas inlet 5-2a and the reactive gas inlet 5-3a, Predetermined at a position corresponding to a height (a≈b) of about ½ of the vertical distance from the ceiling of the space A (the peripheral edge of the hemispherical partition plate 5-1) to the bottom of the hemispherical partition plate 5-1. The mixed gas can be efficiently blown out. The mixed gas outlet 5-4 is not limited in its position and shape as long as the mixed gas blowing port 5-4 is configured to be efficiently introduced into the space B after the raw material gas and the reactive gas are stirred and mixed.
[0038]
As shown in FIGS. 4, 5A and 5B, the gas outlet 5-4 is provided in the vicinity of the source gas introduction pipe 5-2, and violently convects at the outlet. The mixed gas is smoothly introduced into the space B through the gas outlet 5-4. This gas outlet 5-4 may be provided in the vicinity of the reaction gas introduction pipe 5-3. Also in this case, as described above, since the volume of the space B is larger than the volume of the space A, when the mixed gas is introduced from the space A into the space B, a diffusion phenomenon occurs due to the difference in volume. Even when the molecular weights of the source gas and the reaction gas are greatly different from each other, they are uniformly mixed, and the uniformly mixed gas is introduced into the gas heads connected to be separated from each other and becomes turbulent in the reaction chamber. Without being supplied to the substrate.
The source gas introduction pipe 5-2 and the reaction gas introduction pipe 5-3 are partitioned at a position corresponding to the central portion (near the inflection point) of the partition plate 5-1, in the upper part of the space A of the mixer 5. It is attached at a point-symmetrical position with respect to the center point of the plate 5-1, and the gas introduction ports 5-2a and 5-3a are arranged so that their gas introduction directions face each other as described above.
[0039]
As described above, the partition plate 5-1 is formed in a hemispherical shape having a convex partition surface having a quadratic curve shape, and is attached with the source gas introduction pipe 5-2 and the reaction gas introduction pipe 5-3. It is desirable that the mixer is mounted so that there is no gap in the ceiling. As described above, this partition plate may be provided so as not to cause a gap with respect to each gas introduction side wall surface to the mixer, and as long as each introduced gas can be sufficiently stirred and mixed, You may provide so that a clearance gap may be produced between a partition plate and the ceiling part of a mixer.
As described above, it is desirable that the interior of the mixer 5 is partitioned into the spaces A and B by the partition plate 5-1, so that the volume of the space B is larger than the volume of the space A. In the case of the present embodiment, the ratio of the volume of the space A to the volume of the space B is not particularly limited. However, from the viewpoint of satisfactorily performing stirring / mixing and diffusion, it is usually 1: 5 to 1: 2. It is desirable to set the degree.
[0040]
In the mixer 5 configured as described above, the raw material gas introduction pipe 5-2 and the reaction gas introduction are performed in a state where the inside of the reaction chamber 2 separated from the mixer and connected via the gas pipe is evacuated. At least one source gas and a reactive gas are introduced into the space A of the mixer 5 from the pipe 5-3 through the gas inlets 5-2a and 5-3a, respectively. As a result, as shown in FIGS. 5A and 5B, in the space A, the raw material gas flow is divided by the reaction gas flow, and both of the gases on the surface of the partition plate 5-1 are the plate 5-1. As a result, convection is generated, and the raw material gas and the reaction gas are stirred and mixed. Next, as shown in FIG. 4, the mixed gas composed of the mixed source gas and reaction gas is smoothly introduced and diffused into the space B through the gas outlet 5-4. Since the volume of the space B is larger than the volume of the space A as described above, when the mixed gas is introduced from the space A into the space B, a diffusion phenomenon occurs due to the difference in volume, and the uniform mixed gas It is introduced as a stream and diffused.
[0041]
The flow of the raw material gas and the reactive gas in the space A and the tendency of the fluid analysis result of the gas distribution will be described in detail with reference to FIGS. 5 (A) and 5 (B). The analysis was carried out by changing the flow rate (gas concentration 100%) and the ejection speed from the gas inlets 5-2a and 5-3a to the space A with respect to the actual film formation conditions and gases other than the gas used and the gas used. . As a result, the positions of the relatively dense regions of the source gas and the reaction gas (there are countless examples of typical regions) remain the same, but only the ranges are different, and all trends Was the same. The direction of gas flow (gas vector) is very complicated. In particular, the gas vector in the vicinity of the inner wall of the hemispherical partition plate 5-1 has no regularity. The only regularity is that at the bottom of the hemispherical partition plate 5-1, a relatively dark region of each gas tends to be reversed with respect to the positional relationship between the source gas inlet 5-2a and the reaction gas inlet 5-3a. A relatively dense region of the reaction gas exists between the source gas inlet 5-2a and the mixed gas outlet 5-4, and a relatively dense region of the source gas on both sides of the source gas inlet 5-2a Exists. According to this analysis result, it is understood that convection, stirring, and mixing are performed very efficiently in the space A. Therefore, in CVD film formation using a raw material solution, even if continuous film formation is performed, there are few particles, and a film having a good film quality and composition can be stably mass-produced with good reproducibility for a long period of time.
[0042]
In the thin film manufacturing apparatus of the present embodiment, as described above, particle traps are arranged in various parts of the apparatus. Hereinafter, the particle traps will be described.
When a thin film is manufactured by a CVD method such as MOCVD, as described above, in order to manufacture a thin film having a uniform film quality and film thickness distribution on the substrate, a uniform deposition gas is formed in the reaction chamber or directly above the substrate. A smooth flow distribution, a uniform concentration distribution, and a uniform temperature distribution are required, and the smaller the fine particles contained in the deposition gas, the better. However, when producing a thin film by the conventional technology, even if the raw material gas is introduced into the reaction chamber through the filter member or the filter member is provided in the mixer, the number of particles on the initial substrate of the production lot increases. Is seen.
[0043]
Therefore, in order to solve the above problem, it is desirable to install a temperature-controllable particle trap in the vaporizer, gas pipe, mixer, or the like. Each of these particle traps reacts with particles generated when vaporizing the raw material liquid, particles generated / growth with a part of the raw material gas already vaporized from the vaporization section, and the raw material gas. Any device that functions to capture particles generated at the moment of contact with gas and prevent the particles from flowing downstream can be used. Further, the particle trap installed in the gas head may be any one that functions to capture particles that may be generated in a very small amount in the flow path after the mixer in the final stage immediately before the reaction chamber.
[0044]
Although not shown in the figure by opening the valve V2, the vaporized solvent gas can be introduced into the vaporizer, the raw material gas pipe, and the mixer so that the vaporizer, the raw gas pipe, the mixer, etc. You may comprise so that the particle trap arrange | positioned inside and these may be wash | cleaned with solvent gas. In particular, the amount of particles generated when the raw material liquid is vaporized and the particles generated when the raw material gas and the reactive gas are in contact with each other are the particles generated / growth with a part of the already vaporized raw material gas serving as a nucleus. It is much larger than the amount generated. Therefore, the particle traps installed inside the vaporizer and inside the mixer to catch each of these particles are easily clogged, so these two particle traps can be cleaned to eliminate clogging and the particles. It is preferable to arrange and configure the apparatus so that a solvent gas containing a large amount of gas does not flow into the reaction chamber. Moreover, according to this structure, the particle trap installed in the vaporization part, source gas piping, and a mixer can be wash | cleaned not only for every film-forming lot but for each board | substrate film-forming.
[0045]
According to the present embodiment, for example, as shown in FIG. 1, the particle trap includes an upstream side pipe of the valve V3 attached to the inside of the vaporizing unit 7b and the source gas pipe 6 connected to the vaporizing unit, Inside the mixer 5, upstream of the valve V <b> 1 attached to the pipe 4 connected to the mixer 5, upstream of the pipe 10 connecting the pipe 4 and the exhaust system 1, and downstream of the gas head 3. These are temperature-controllable particle traps provided as P1 to P6, respectively, immediately before the shower hole. There are no particular restrictions on the material, shape, etc. of these traps as long as they have a function of capturing particles generated at each location.
[0046]
The particle trap P1 provided in the vaporizer 7b functions as a temperature-controllable trap for capturing and removing particles generated when the raw material liquid is vaporized, and the particle trap P2 has already been vaporized. This is for capturing / removing particles in the raw material gas pipe 6 where a part of the raw material gas is generated / grown, and the particle trap P3 detects particles generated at the moment when the raw material gas and the reactive gas contact each other. The particle trap P4 is for trapping / removing particles generated in the film forming gas pipe 4. The particle trap P5 is a pipe connected to the mixer 5 4 for capturing and removing particles generated in the pipe 10 connecting the exhaust system 1 and the exhaust system 1, each of which is on the downstream side To function so that it does not shed particles. The particle trap P6 installed in the gas head 3 functions to capture particles that may be generated in a very small amount in the flow channel after the mixer in the final stage immediately before the reaction chamber.
[0047]
The particle trap is not particularly limited as long as its arrangement and configuration are capable of collecting particles and can be cleaned. For example, it is desirable that the temperature can be controlled independently of the piping by a heating means such as a heater.
The material of the particle trap is determined in consideration of the corrosion resistance, mechanical characteristics, heat resistance (about 300 ° C.), etc. against the source gas and the reaction gas. For example, nickel or an alloy thereof (for example, Hastelloy (registered trademark), Inconel (registered trademark), etc.), stainless steel (316, 316L, etc.), aluminum, titanium, ceramics, or the like can be selected. Moreover, you may arrange | position the porous body filter which is what is called a metal sintering filter which can control temperature with this particle | grain trap.
According to the present embodiment, by arranging the particle trap as described above, the pressure loss is small, the trapping amount is large, there is no clogging, and dry / wet particles are efficiently trapped. Therefore, there are almost no particles in the film forming gas introduced into the reaction chamber.
[0048]
Next, isotropic exhaust in the reaction chamber will be described.
As shown in FIG. 1, an inert gas or the like is flowed around the gas head 3 in order to suppress the turbulent flow and to have a rectifying action and to prevent the film from adhering to the inner wall of the reaction chamber 2. Also good.
A pipe V7 is provided in the pipe 12 through which the inert gas flows around the gas head, and gas is supplied to one end of the pipe via a heat exchanger 13 and then flow rate control systems (MFCs) 22 and 23, respectively. Sources 22-1 (for example, a reactive gas source) and 23-1 (for example, an inert gas source) are connected, and the other end is connected to the reaction chamber 2. A gas pipe 11 connected to the film forming gas pipe 4 is connected to an arbitrary portion of the pipe 12. Therefore, since it is possible to flow an inert gas or a reaction gas or a mixed gas of an inert gas and a reaction gas in an arbitrary ratio into the reaction chamber 2, the reaction gas temperature rise or inertness corresponding to the process / substrate is increased. It is possible to increase the temperature of the gas or to increase the temperature of the mixed gas of the inert gas and the reactive gas in any ratio. Further, during non-film formation (valve V1: closed, valve V2: open), the pressure in the reaction chamber 2 is always maintained by these gases and the pressure adjusting valve 1a even when the substrate is transported or when the temperature is raised. It can be kept constant at the same pressure as during film formation. Therefore, the substrate temperature change due to the pressure change is small and stable film formation can be performed, and the stress to the film due to the pressure change can be reduced, and the peeling of the film formed on the high temperature part such as the substrate stage 2-1 is suppressed. The maintenance cycle can be extended. Similarly, a reaction gas source and an inert gas source are connected to a reaction gas pipe connected to the mixer 5 together with a flow rate control system. At the time of film formation, only the reaction gas or the reaction gas and the inert gas Can be introduced into the mixer at an arbitrary ratio, and the raw material gas can be uniformly mixed in the mixer.
[0049]
As described above, the thin film manufacturing apparatus has a cylindrical reaction chamber 2, and a cylindrical substrate stage 2-1 on which a substrate such as a silicon wafer is placed is provided in the reaction chamber. It has been. This substrate stage incorporates a heating means for heating the substrate. The reaction chamber 2 also includes means for configuring the substrate stage 2-1 to be movable up and down between the film formation position in the reaction chamber and the substrate transfer position below the reaction chamber. A gas head 3 is provided in the central portion on the upper side of the reaction chamber 2 so as to face the substrate stage 2-1, so that the film forming gas from which particles are removed is ejected from the gas head 3 toward the central portion of the substrate. It is configured.
Incidentally, when a thin film is produced on a substrate by a CVD method such as the MOCVD method, when the source gas is lowered below a certain temperature, the source gas is precipitated as particles, which may cause film formation dust in the reaction chamber. Therefore, conventionally, a heat exchanger, which is a gas temperature adjusting means, is provided in the reaction gas pipe, and a heater or the like is provided on the outer wall of the reaction chamber 2 or the substrate stage 2-1 in order to prevent the deposition of the source gas. A heating means is provided.
[0050]
Here, in the MOCVD process, in order to make the film thickness distribution and composition distribution of the thin film to be manufactured on the substrate uniform and to improve the reproducibility thereof, exhaust gas containing a mixed gas that does not contribute to the process is emitted from the periphery of the substrate. It is important that the gas flow from the gas head 3 to the exhaust system 1 is made uniform by exhausting the air. In particular, it is necessary to prevent the occurrence of convection and turbulence in the first space C (FIG. 1) below the gas head 3 and above the substrate stage 2-1. For this purpose, as shown in FIG. 1, it is desirable to surround the periphery of the substrate stage 2-1 with a sleeve member 2-2 having a predetermined height L. In this case, the volume of the second space D below the substrate stage is set so that the exhaust gas is isotropically exhausted through an annular gap (r) formed by the sleeve member 2-2 and the inner wall surface of the reaction chamber 2. It is set larger than the volume of the first space C.
[0051]
As described above, when a heating unit is incorporated in the substrate stage 2-1 in order to heat the substrate to a predetermined temperature, thermal convection can occur above the substrate. Therefore, a gas ring 2-3 for uniformly introducing an inert gas into the reaction chamber along the inner wall surface of the reaction chamber 2 is provided on the upper portion of the reaction chamber 2 so as to surround the gas head 3. Due to the forced rectification of the inert gas injected from the gas ring 2-3, the gas passes through the gap r between the sleeve member 2-2 and the inner wall surface of the reaction chamber 2 and is exhausted into the second space D. The exhaust gas can be isotropically exhausted more reliably from the periphery of the sleeve member 2-2. Thereby, turbulent flow, convection, and thermal convection in the first space C can be prevented.
[0052]
By the way, as shown in FIG. 7A, when the distance from the gas head 3 to the substrate stage 2-1 is long, the height position of the substrate stage 2-1 in the reaction chamber 2 is not exhausted and reacts. Convection E can occur in the upper corner of the chamber. On the other hand, as shown in FIG. 7B, when the distance from the gas head 3 to the substrate stage 2-1 is short, the film forming gas ejected from the gas head is reflected by the substrate and is located above the reaction chamber 2. Convection E can occur at the corners. For this reason, the distance between the gas head 3 and the substrate stage 2-1 at the film formation position is set to a distance at which such convection E hardly occurs.
In addition, when the substrate transport port for transporting the substrate to the substrate stage 2-1 is provided at a position facing the first space C, turbulent flow may occur around the substrate transport port. Therefore, an elevating means (not shown) is attached to the substrate stage 2-1 so that the substrate stage 2-1 can be raised and lowered between the film forming position on the upper side of the reaction chamber 2 and the lower substrate transfer position. To do. A substrate transfer port is provided in the reaction chamber 2 corresponding to the substrate transfer position.
In the case of the thin film manufacturing apparatus shown in FIG. 1, in order to adjust the temperature of the inert gas ejected from the gas ring 2-3 so that the source gas does not precipitate as particles in the MOCVD method, the gas pipe 12 leading to the gas ring A heat exchanger as a temperature adjusting means may be provided. This gas pipe is provided with a valve V7.
[0053]
As described above, the thin film manufacturing apparatus of the present invention includes a mixer in which a partition plate having a specific shape is disposed, and a mixed gas obtained by stirring and mixing in the space A of the mixer is introduced into the space B. In this case, the light is naturally diffused by a diffusion phenomenon caused by the difference in volume between the spaces A and B. In addition, the specific vaporization system, mixer, reaction chamber and exhaust system are configured to have a predetermined arrangement, and preferably, particles traps are provided at various locations of the thin film manufacturing apparatus and particles generated, adhered and captured A means for cleaning and removing the gas is provided, and more preferably, a sleeve member and a gas ring are provided in the reaction chamber. For this reason, if this apparatus is used, it is possible to manufacture a thin film having a good film quality with a very simple configuration with good reproducibility. In other words, since the deposition gas with few particles and mixed uniformly can be introduced into the reaction chamber, the deposition gas does not become turbulent in the reaction chamber, and the particles in the apparatus are regularly Therefore, it is possible to improve and stabilize the film quality and film thickness distribution of the manufactured thin film.
[0054]
The present invention is not limited to the above embodiment, and various changes can be made. For example, for the partition plate, a hemispherical partition plate is used as an example in the above, but the curvature, shape (for example, cylindrical shape, cube shape, conical shape), size, etc. of this partition plate are the same as the gas used. The design can be changed as appropriate according to the type and process. In addition, as for the position and shape of the gas outlet provided in the partition plate, as long as the raw material gas and the reactive gas are stirred and mixed in the space A and then introduced into the space B uniformly, The design can be changed accordingly. As described above, the gas mixture can be smoothly introduced into the space B by providing the gas outlet near the portion where the gas in the space A violently convects. For example, if a gas outlet is provided within a range of 45 degrees from the center point of the straight line connecting the source gas inlet and the reactive gas inlet to the vertical direction of the straight line, both gases are mixed uniformly and smoothly It can be introduced into the space B.
[0055]
In the above embodiment, a mixer having one space A and B has been described as an example. However, gas mixing may be performed by providing two or more spaces A and B. Is possible. Further, depending on the degree of the mixed state, it is possible to carry out the reaction by introducing the film forming gas from the space A into the reaction chamber as it is through the pipe without providing the space B.
The above-mentioned mixer has a special effect when a raw material that is liquid at room temperature is used in the MOCVD method. This is because raw materials that are liquid at room temperature are heavy even when vaporized.
If the above-described thin film manufacturing apparatus is used, a raw material containing Pt, Ir, Ru or the like as a raw material source, for example, Pb (DPM) as a liquid raw material₂, Zr (DMHD)₄Ti (i-PrO)₂(DPM)₂CVD film formation of a ferroelectric film PZT using CVD, CVD film formation in which additive elements such as La, Sr, Ca, Al and the like are added to this PZT, and Ba (DPM) as a liquid material₂, Sr (DPM)₂Ti (i-PrO)₂(DPM)₂Can be used for CVD of the ferroelectric film BST, and thin films mainly used for metal wiring such as Cu and Al, TiN, TaN, ZrN, VN, NbN, Al₂O₃A thin film mainly used for barriers such as SDT, STO and other dielectric thin films, and films obtained by adding additive elements such as La, Sr, Ca and Al to this dielectric can be manufactured by the CVD method. .
[0056]
【Example】
Hereinafter, examples and comparative examples of a method for forming a metal oxide thin film by MOCVD using the thin film manufacturing apparatus of the present invention will be described with reference to the drawings.
Example 1
In this embodiment, an example of forming a ferroelectric PZT film by MOCVD will be described.
PZT source gas and oxygen gas (O₂), The PZT thin film was manufactured using the thin film manufacturing apparatus shown in FIG.
[0057]

[0058]
The arranged particle traps were as follows.
Vaporizer internal particle trap: For particle size of 1.0μm
Mixer particle trap: For particle size of 0.5μm
Raw material gas / deposition gas piping particle trap: For particle size of 0.5μm
Gas head particle trap: For particle size of 0.3μm
The film forming pressure was always adjusted to 5 Torr using a pressure adjusting valve, an inert gas, and a reactive gas. At this time, the pressure in various parts of the apparatus was 14 Torr in the space B of the mixer and 19 Torr in the vaporization section. Generally, the stable vaporization of the liquid raw material is desirably 30 Torr or less, and the requirement is sufficiently satisfied.
[0059]
In the mixer 5 provided with the hemispherical partition plate shown in FIG. 1, the raw material gas and the reaction gas are respectively supplied from the gas introduction ports 5-2a and 6-3a through the gas introduction pipes 5-2 and 5-3. The mixture was introduced into the mixer, stirred, mixed, and diffused, and a film forming gas was introduced into the reaction chamber 2 from the mixer, and a PZT thin film was formed on the substrate under the above conditions by the MOCVD method in the reaction chamber. Moreover, the same film-forming process was performed using the mixer which does not provide a partition plate. The outline of the film thickness distribution of the thin film thus formed is shown in FIGS. In the figure, 71 is a substrate, 72 is a thick part, and 73 is a thin part. As is clear from FIG. 8A, when a mixer without a partition plate is used, a thin film portion 73 is formed on the raw material gas inlet side, and a thick film portion 72 is formed on the reactive gas inlet side. It was done. This is because, in the space A + B where the partition plate is removed, a reversal phenomenon of a relatively dense region of each gas occurs at the bottom of the space A + B with respect to each gas inlet position, which is found in the fluid analysis, from the film forming gas outlet. It is easily guessed that the density distribution is transferred onto the substrate as a laminar flow with the reversal phenomenon being dragged to the gas head. The film thickness distribution at this time was ± 6.3%. From the viewpoint of device fabrication, a film thickness distribution of 3% or less is definitely necessary to increase the yield of semiconductor chips, so the thin film obtained using a mixer without a partition plate is a problem. .
[0060]
On the other hand, when a mixer provided with a partition plate is used (the positions of the introduction ports for the source gas and the reaction gas are the same), as is clear from FIG. A thin film having a uniform film thickness could be continuously produced with a film thickness distribution of ± 1.2%. This is because the partition plate efficiently performs convection, stirring, mixing, and diffusing in each of the spaces A and B, and the source gas and the reaction gas are uniformly mixed. From the viewpoint of device fabrication, it sufficiently satisfied ± 3% or less necessary for increasing the yield of semiconductor chips.
In FIG. 9, when there is no particle trap, when the particle trap is installed in the vaporization section, source gas / film formation gas piping, mixer, gas head, and when the particle trap is cleaned for each substrate And the change in the total number of accumulated particles (size of 0.2 μm or more). A vaporizing member is provided inside the vaporizing unit except for the case where there is no particle trap in FIG. The number of particles was measured on the second, fifth, fifteenth, and twenty-fifth substrates of each lot in one lot: 25 sheets × 4 lots = 100 sheets.
[0061]
In FIG. 9, when the particle trap is installed in the vaporization part (1) in the graph indicated by ●, the graph indicated by □ is the particle trap in (1) + mixer (2). If the particle trap is installed in (1) + (2) + source gas / film formation gas piping (3), the graph displayed with ▲ is ▲ 1 When a particle trap is installed at ▼ + ▲ 2 ▼ + ▲ 3 ▼ and solvent gas cleaning is performed, the graph indicated by △ is ▲ 1 ▼ + ▲ 2 ▼ + ▲ 3 ▼ + ▲ 4 ▼ When the particle trap is installed and solvent gas cleaning is performed, the graph indicated by ◯ shows the result when the particle trap is not installed.
[0062]
As is apparent from FIG. 9, when the apparatus does not have a particle trap, the number of particles falling on the substrate tends to increase as the substrate is processed. The amount is already enormous and the adverse effect on the film quality is certain, and it can be predicted that it will continue to increase even after processing 100 sheets. Also, since the number of initial particles is small compared to the latter half, the amount of generated particles is large, but it is unlikely that the amount of generated particles is increasing inside the vaporization section. It is surmised that it overflows and flows downstream.
[0063]
When the vaporizing member and the particle trap are installed inside the vaporizer (in the case of (1) in FIG. 9), the total number of particles is reduced to about 1/8 compared to the case without the particle trap. The vaporization member installed in the vaporization section vaporizes most of the raw material liquid particles that are going to flow downstream, reducing the particles themselves, reducing the liquid particles flowing to the particle trap, and the particle trap is the vaporization section Most of the particles that flow into the gas from the vaporization part were reduced because the particles flowing downstream from the gas and the extremely small amount of liquid particles that escaped vaporization by the vaporization member were vaporized.
[0064]
When a particle trap is installed in the vaporizer and inside the mixer (in the case of (1) + (2) in FIG. 9), the source gas and the reaction gas are obtained by installing the particle trap in the mixer. Particles generated upon contact with the substrate are captured, and the total number of particles measured on the substrate in the reaction chamber is smaller than in the case of (1). However, after processing 100 sheets, the total number exceeds 1000, and the adverse effect on the film quality is certain, and it can be predicted that it will continue to increase after processing 100 sheets of substrates. Also, what is impressive is that a large increasing trend is seen after one lot (25 substrates). For this reason, in addition to the particles that are generated / growth with a part of the source gas already vaporized in the film forming gas downstream from the mixer, the effectiveness of capturing the particles of the particle trap is reduced from a certain time. Therefore, it is considered that the number of particles flowing downstream and measured in the reaction chamber is increasing. FIGS. 10A and 10B show micrographs of the particle trap installed in the mixer. The generated particles have a size smaller than 0.2 μm, but are captured in a form that adheres to the steel wire of the particle trap that overlaps several times. When this steel wire is covered with particles, it becomes difficult for the particle trap to capture the particles, and the particles gradually flow downstream. Therefore, it is necessary to clean and remove the particles in the particle traps regularly or as needed so that the particles do not cover the steel wire of the particle traps, that is, do not saturate. is there.
[0065]
When a particle trap is installed in the raw material gas pipe and the film forming gas pipe in addition to the vaporizer and the mixer (in the case of (1) + (2) + (3) in FIG. 9), Similar to the behavior in the case of (1) + (2), it increases for each substrate, but the increasing tendency is delayed by about 1 lot. This is not a fundamental solution because the increase in the number of particle traps has only increased the time to saturation of the particle traps.
Therefore, when the substrate is cleaned with a solvent gas in a state where the particle trap is installed in the vaporizer, the mixer, the source gas pipe, and the film forming gas pipe ((1) + (2) + ▲ in FIG. 9). In the case of (3) + (5)), the number of particles slightly increases after 50 substrates, but from there, the number of particles is stable at about 100 or less. As described above, in order to sufficiently perform the function of the particle trap installed at various places in the apparatus in the CVD method in which the liquid source is vaporized and used as the source gas, it is necessary to clean the particle trap periodically or as needed.
[0066]
Furthermore, in this embodiment, when a particle trap is also provided in the gas head (in the case of (1) + (2) + (3) + (4) + (5) in FIG. 9), the device Since the number of particles flowing into the gas head is minimized by capturing the particles at each location and cleaning the trap, the particle traps in the gas head are not easily clogged, and the maintenance cycle is much longer than other traps. Further, since the particles flowing into the reaction chamber in the final stage immediately before the reaction chamber can be captured, the number of particles measured in the reaction chamber is further reduced.
Particle traps placed in various parts of the apparatus will affect the PZT composition ratio. FIG. 11 shows changes in the composition of the Pb / (Zr + Ti) and Zr / (Zr + Ti) ratio when a particle trap is installed in the vaporizer, mixer, and source gas / film forming gas pipe. The number of particles was measured on the 3rd, 14th and 24th substrates in each lot of 1 lot: 25 × 4 lots = 100.
[0067]
As is apparent from FIG. 11, although the Zr / (Zr + Ti) ratio does not change, the Pb / (Zr + Ti) ratio decreases each time the substrate processing is repeated. This indicates that only the Pb element is attached to the particle traps arranged at various places in the apparatus, and that the amount of the Pb element attached gradually increases. It is considered that the increase in the adhesion amount of Pb element is related to the fact that the amount of particles deposited on the particle trap changes with time as described above.
Next, FIG. 12 shows a case where there is no particle trap, a case where a particle trap is installed in a vaporizer, a mixer, a source gas / film formation gas pipe, a gas head, and a cleaning of the particle trap for each substrate. Shows the change in the composition of the Pb / (Zr + Ti) ratio.
[0068]
As is clear from FIG. 12, the Pb / (Zr + Ti) ratio for each substrate does not decrease between the case where no particle trap is installed and the case where a vaporizer and particle trap are installed inside the vaporizer. However, every time a mixer, source gas / film forming gas pipe, gas head, and particle trap are added, a decreasing tendency of the Pb / (Zr + Ti) ratio for each substrate appears strongly. The Pb element is preferentially captured by the particle trap. On the other hand, when the particle trapper cleaning for each substrate is performed, the tendency of decreasing the Pb / (Zr + Ti) ratio is somewhat suppressed. From this point of view, in terms of thin film composition control, the application of the particle trap at each location is to prevent particles from covering the steel wire of the particle trap, that is, not to saturate regularly or from time to time. It is necessary to clean and remove the particles in the vessel.
[0069]
Moreover, it is possible to prevent the preferential adhesion of Pb element by raising the temperature of the particle traps arranged in various parts of the apparatus. FIG. 13 shows a Pb / (Zr + Ti) ratio for each substrate when a vapor trap, a mixer, a raw material gas / film formation gas pipe, a particle trap are installed in the gas head, and each temperature setting is given every 10 ° C. Shows changes. As is apparent from FIG. 13, the decrease in Pb / (Zr + Ti) decreases as the temperature of the particle trap increases, and the decrease in the Pb / (Zr + Ti) ratio disappears when the temperature of the particle trap is increased by 20 ° C. or more. .
In this example, when the set temperature of each part of the apparatus was 210 ° C., the temperature of each part of the apparatus and the particle trap was 205 to 210 ° C. From this, when the temperature of the particle trap was + 20 ° C., that is, when the set temperature was 230 ° C., the temperature of the particle trap was 225 ° C. to 230 ° C. Therefore, the temperature of the particle trap in each part of the apparatus excluding the vaporization section is set to 225 ° C. or more, and the particle trap is cleaned periodically or as needed to prevent the preferential adhesion of the Pb element to the particle trap. However, a stable thin film can be continuously formed with good reproducibility.
[0070]
Here, reference is made to the vaporizing member and the particle trap in the vaporizing section.
The vaporization member and the particle trap in the vaporization part were set to the optimal temperature for vaporization. This is because if the vaporization temperature is set to be insufficient, the influence on the downstream side is too strong, and thus each influence cannot be seen. The temperature at which the liquid raw material is vaporized is set to 240 ° C., and the temperature of the vaporizing member and the particle trap in the vaporizing section at this time is set to 240 ° C. so that sufficient vaporization can be achieved. The actual temperature of the particle trap was 240-245 ° C. Therefore, the vaporization member and the particle trap inside the vaporization section were at a temperature at which preferential adhesion of the Pb element did not occur. However, the particles are greatly reduced as seen in the case of (1) in FIG. 9, but the Pb / (Zr + Ti) ratio does not show a decreasing tendency as seen in the case of (1) in FIG. . The fluctuation tendency of the Pb / (Zr + Ti) ratio with respect to the amount of captured particles is different from other particle traps. In addition to the high temperature of 240 ° C. or higher, the vaporization member and the particle trap in the vaporizer have a structure that focuses on the efficient vaporization of the droplets flowing downstream, and the liquid droplets are generated in the particle trap. This is largely due to the unique condition of vaporization.
[0071]
Further, although not remarkably observed in this example, the decrease in the Pb element in the film means that the film thickness corresponding to the reduced element amount decreases. Therefore, the composition variation leads to instability of the film formation rate. In other verifications of the present inventors, when the Pb / (Zr + Ti) ratio is decreased by 0.4, the film thickness is decreased by about 10 to 15 nm, and the film thickness distribution in which mixing of the source gas and the reaction gas is dominant is changed. Has been confirmed (not shown). Therefore, the temperature of the particle traps at various places in the apparatus is set to 225 ° C. or higher, and the particle traps are cleaned periodically or as needed to prevent the preferential adhesion of Pb elements to the particle traps, and the film thickness is stable. Can be formed continuously with good reproducibility.
[0072]
As described above, in the above film formation example, a mixer capable of uniformly mixing the source gas and the reaction gas is provided, and the mixer has an arrangement configuration that does not affect the film quality at the initial stage of film formation and at the end of film formation, and is transported. At the time of film formation, non-film formation, the pressure inside the reaction chamber is kept constant to prevent film peeling, and the vaporization member inside the vaporization section and the particle trap increase the vaporization efficiency, and particles from the vaporization section In addition, particle traps are placed at various locations in the equipment, particles flowing into the reaction chamber are suppressed, and the particle trap is structured to be washable, and the temperature of the particle trap is plumbed. Since the composition fluctuation and film thickness fluctuation can be suppressed by making it higher than the temperature, the film thickness distribution / composition distribution / film deposition rate is good and stable, the film deposition dust is small, and continuous film deposition is stably reproduced. Well done.
[0073]
(Example 2)
Evaluation was also performed in the BST process in the same manner as in Example 1. BST source gas and oxygen gas (O₂), The BST thin film was manufactured using the thin film manufacturing apparatus shown in FIG.

[0074]
The arranged particle traps were as follows.
Vaporizer internal particle trap: For particle size of 1.0μm
Mixer particle trap: For particle size of 0.5μm
Raw material gas / deposition gas piping particle trap: For particle size of 0.5μm
Gas head particle trap: For particle size of 0.3μm
The film forming pressure was always adjusted to 8 Torr using a pressure adjusting valve, an inert gas, and a reactive gas.
In the mixer 5 provided with the hemispherical partition plate shown in FIG. 1, the raw material gas and the reaction gas are respectively supplied from the gas introduction ports 5-2a and 6-3a through the gas introduction pipes 5-2 and 5-3. The mixture was introduced into the mixer, stirred, mixed, and diffused, and a film forming gas was introduced into the reaction chamber 2 from the mixer, and a BST thin film was formed on the substrate under the above conditions by the MOCVD method in the reaction chamber. Moreover, the same film-forming process was performed using the mixer which does not provide a partition plate. As a result, in the case of the present invention, the same effect as in Example 1 was obtained.
[0075]
(Example 3)
Evaluation was also performed in the Cu process in the same manner as in Example 1. Source gas for Cu thin film and hydrogen gas (H₂The Cu thin film was manufactured using the thin film manufacturing apparatus shown in FIG.

[0076]
The arranged particle traps were as follows.
Vaporized internal particle trap: For particle size of 5.0μm
Mixer particle trap: For particle size of 0.3μm
Raw material gas / deposition gas piping particle trap: For particle size of 0.3μm
Gas head particle trap: For particle size of 0.1μm
The film forming pressure was always adjusted to 0.8 Torr with a pressure adjusting valve, an inert gas, and a reactive gas.
In the mixer 5 provided with the hemispherical partition plate shown in FIG. 1, the raw material gas and the reaction gas are respectively supplied from the gas introduction ports 5-2a and 6-3a through the gas introduction pipes 5-2 and 5-3. The mixture was introduced into the mixer, stirred, mixed, and diffused, and a film forming gas was introduced into the reaction chamber 2 from the mixer, and a Cu thin film was formed on the substrate under the above conditions by the CVD method in the reaction chamber. Moreover, the same film-forming process was performed using the mixer which does not provide a partition plate. As a result, in the case of the present invention, the same effect as in Example 1 was obtained.
[0077]
The thin film production apparatus and production method of the present invention can be applied to all CVD film formation using a raw material gas by vaporizing a liquid raw material in addition to the above-described embodiments.
According to the present invention, in addition to the above embodiment, it is possible to vaporize a liquid source and use it as a source gas, to uniformly mix a source gas having a mass difference and a reaction gas, and to set a reaction chamber pressure to The pressure is adjusted according to the raw material elements and can be kept constant at all times. If the vaporization conditions (vaporization temperature, carrier gas, vaporization pressure) are set appropriately, the raw material liquid particles can be efficiently used regardless of the type of raw material liquid. Vaporization is also possible, and particles that flow into the reaction chamber can also be suppressed by appropriately arranging the particle traps with appropriately selected eye roughness at various locations including the vaporization section. It is also possible to prevent specific elements required for the reaction from adhering to the particle trap by setting the temperature of the particle trap at various locations to an appropriate temperature that is higher than the piping temperature that matches the raw material. , Still more, the internal and pipes particle trap or system various parts disposed in the apparatus various places are washable. For this reason, in the CVD method using a gas obtained by vaporizing a liquid source and a reaction gas as a film forming gas, the film thickness distribution, composition distribution, and film forming rate are good and stable, the film forming dust is small, and the continuous film forming is stable. Thus, it is possible to establish a thin film manufacturing apparatus and a manufacturing method thereof that can be performed with good reproducibility.
[0078]
【The invention's effect】
As described above, according to the present invention, in the CVD thin film manufacturing apparatus, each component of the apparatus including the particles captured by the particle trap disposed in the vaporization section, the mixing chamber, the gas head, and the gas pipe, and the gas pipe By adopting a structure that cleans and removes particles generated and adhered to the elements, the life of the particle traps in various parts of the apparatus can be extended, and as a result, the apparatus operating time can be extended. In addition, this cleaning can reduce the amount of specific elements required for the reaction adhering to the particle trap, and as a result, film composition fluctuations and film thickness fluctuations can be suppressed. It is good and stable, and there is little film formation dust, and continuous film formation can be performed stably and with good reproducibility.
[0079]
According to the present invention, in addition to the effect of this cleaning, a mixer that can uniformly mix the source gas and the reaction gas is provided, so that the turbulent flow for mixing is not brought into the reaction chamber, and the film thickness distribution and The reproducibility is improved, and since the mixer has an apparatus structure and arrangement that does not affect the film quality at the initial stage of film formation and at the end of film formation, the film quality and its reproducibility are improved. Furthermore, in such a structure, the pressure in the reaction chamber can be kept constant during transport, film formation, and non-film formation, so that film peeling is suppressed, the operation time of the apparatus is extended, and particles are Can be reduced. Furthermore, the vaporization member inside the vaporization unit and the particle trap increase the vaporization efficiency and suppress the generation of particles from the vaporization unit, and extend the life of the particle traps at various locations in the downstream of the device. In addition to extending the operating time, the particle traps arranged in various parts of the apparatus can suppress the particles flowing into the reaction chamber and reduce the particles on the substrate that cause defects in the product.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a configuration of a thin film manufacturing apparatus of the present invention.
FIG. 2 is a schematic configuration diagram of a vaporization system in the thin film manufacturing apparatus of the present invention shown in FIG.
3 is a schematic configuration diagram inside a vaporization section in the thin film manufacturing apparatus of the present invention shown in FIG. 1, wherein (a) is a cross-sectional view thereof, and (b) is a perspective view thereof. FIG.
4 is a schematic sectional view of a mixer in the thin film manufacturing apparatus of the present invention shown in FIG.
5A and 5B are views for explaining gas distribution and gas flow of the mixer shown in FIG. 4, wherein FIG. 5A is a cross-sectional view of a space A portion in the mixer, and FIG. 5B is a top view of the mixer.
FIG. 6 is a graph showing the transition of the total number of particles for each substrate in continuous film formation.
7 is a cross-sectional view of a part of the reaction chamber for explaining the flow of exhaust gas in the reaction chamber of the present invention, (a) is a cross-sectional view when the substrate stage is at the substrate transfer position, and (b). FIG. 4 is a cross-sectional view when the substrate stage is at a film forming position.
FIG. 8 is a top view of a substrate showing a film formation result when there is no partition plate and when there is a partition plate.
FIG. 9 is a graph showing the transition of the total number of particles for each substrate in each continuous film formation.
FIG. 10 is an electron micrograph of a particle trap provided inside the mixer, (a) is an electron micrograph showing the surface state, and (b) is an enlarged photo thereof.
FIG. 11 is a graph showing a composition change (Pb / (Zr + Ti) and Zr / (Zr + Ti)) due to an overall effect when a particle trap is installed in a vaporizer + mixer + raw material gas / gas pipe.
FIG. 12 is a graph showing a composition change (Pb / (Zr + Ti)) under each particle trap installation condition.
FIG. 13 shows a particle trap temperature composition (Pb / (Zr + Ti)) when a particle trap is installed in the vaporizer + gas pipe + mixer + gas head and the particle trap for each substrate is cleaned with solvent gas. ) Is a graph showing the impact on
[Explanation of symbols]
1 Exhaust system 1a Pressure adjustment valve
2 Reaction chamber 2-1 Substrate stage
2-2 Sleeve member 2-3 Gas ring
3 Gas head 4 Deposition gas piping
5 Mixer 5-1 Partition plate
5-2 Source gas inlet pipe 5-2a Source gas inlet
5-3 Reaction gas inlet pipe 5-3a Reaction gas inlet
5-4 Gas outlet 5-5 Deposition gas inlet
6 Raw material gas piping 7 Evaporation system
7a Raw material liquid supply part 7b Vaporization part
7b-1 Nozzle 7b-2, 7b-3 Vaporizing member
7b-4 Particle trap 8 Piping
9, 13 Heat exchanger 10, 11, 12 Piping
20, 21, 22, 23 Mass flow controller
20-1, 21-1, 22-1, 23-1 Reaction gas / inert gas source
A, B, C Raw material liquid D Solvent supply section

Claims (12)

In a membrane production apparatus comprising a raw material supply unit that supplies a raw material solution obtained by dissolving a liquid or solid raw material in a solvent, a vaporization system having a vaporization unit, a mixer, a reaction chamber, and an exhaust system.
Each of the vaporization system, the mixer, the reaction chamber, and the exhaust system are connected by piping;
Providing a temperature-controlled vaporizing member inside the vaporizing section;
The mixer is provided with a pipe for introducing a source gas and a reaction gas so that the gas inlets face each other, and a partition plate having a quadratic curve shape that is convex toward the downstream side is provided therein. The interior of the mixer is partitioned into two spaces, and a gas outlet is provided at a position corresponding to ½ of the vertical distance from the upstream ceiling portion to the downstream bottom portion of the partition plate. The reaction gas is uniformly mixed in the mixer, and the obtained film forming gas is configured to be introduced from the mixer to the gas head of the reaction chamber via a pipe.
Providing a pressure regulating valve between the reaction chamber and the exhaust system;
The particle trap was placed at a predetermined location on the device;
Flowing a solvent gas vaporized by the vaporizing portion in the pipe, so that it can be cleaned and removing particles adhered to the generated and apparatus various locations in the apparatus various locations up to the reaction chamber from the vaporization unit, the raw material solution supply unit A film manufacturing apparatus comprising a solvent supply unit that supplies a solvent for particle cleaning / removal and the same solvent that dissolves the raw material . Inside the vaporization unit, equipped with a particle trap that captures particles generated when the raw material liquid is vaporized,
2. The film production according to claim 1, wherein a particle trap is disposed at a predetermined position of the apparatus in order to capture particles generated in the gas path from the vaporization section through the mixer to the reaction chamber. apparatus.   3. The film manufacturing apparatus according to claim 2, wherein the particle trap is disposed in a pipe between the vaporizer and the mixer.   3. The film manufacturing apparatus according to claim 2, wherein the particle trap is disposed in the mixer.   3. The film manufacturing apparatus according to claim 2, wherein the particle trap is disposed in a gas head installed at an upper portion of the reaction chamber.   6. The apparatus according to claim 2, wherein the particles trapped in each of the particle traps are washed and removed by flowing a solvent gas vaporized in the vaporization unit. Membrane manufacturing equipment. In order to prevent the pressure in the reaction chamber from fluctuating when the film forming gas is introduced into or not introduced into the reaction chamber, non-film formation is performed simultaneously with the normal pressure control by the pressure adjusting valve provided between the reaction chamber and the exhaust system. In some cases, the same amount of gas can be flowed as in the film formation, and an inert gas source and a reactive gas source are connected to the secondary side of the mixer together with a flow rate control system so that the inert gas or reactive gas or any ratio The structure according to any one of claims 1 to 6 , wherein the mixed gas of the inert gas and the reactive gas can be introduced into the reaction chamber so that the pressure in the reaction chamber can be controlled. The film manufacturing apparatus as described. In the production operation cycle of the film manufacturing apparatus in which the apparatus standby and continuous film formation are repeated , the pressure control by the pressure adjusting valve and the inert gas or the reactive gas or the inert gas and the reactive gas in an arbitrary ratio are supplied to the reaction chamber. The film manufacturing apparatus according to claim 7 , wherein the structure is such that pressure control by introduction can be continuously performed . The reaction chamber is connected to an inert gas source and a reactive gas source with a flow rate control system interposed therebetween, and an inert gas or a reaction gas or a mixed gas of an inert gas and a reactive gas in an arbitrary ratio is supplied to the reaction chamber. The film manufacturing apparatus according to any one of claims 1 to 8 , wherein the substrate can be heated by a heating means while being directly introduced into the substrate. The reaction gas piping to the mixer is connected to the reaction gas source and the inert gas source with a flow rate control system interposed therebetween, and the inert gas or the reaction gas or an arbitrary ratio of the inert gas is connected in the mixer. The film manufacturing apparatus according to any one of claims 1 to 9 , wherein a mixed gas of an active gas and a reactive gas can be mixed with a raw material gas vaporized in a vaporizing section. Film production apparatus according to any one of claims 1 to 10, characterized in that a valve of the introduction / non-introduction into the reaction chamber of the film forming gas on the secondary side of the mixer. A method for producing a film using the film production apparatus according to any one of claims 1 to 11 , wherein the raw material gas and the reaction gas are stirred and mixed, and the stirring and mixing are performed. A step of diffusing a film forming gas composed of the obtained raw material gas and reaction gas, and introducing the diffused film forming gas containing almost no particles into the reaction chamber to form a film on the object to be formed in vacuum. A step of forming, and a step of washing and removing particles adhering to or trapped in various parts of the apparatus from the vaporization section to the inside of the gas head provided in the upper part of the reaction chamber using a gas of the same solvent as the solvent of the raw material A film manufacturing method comprising:

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